Friday, January 31, 2014

Life Beneath the Snow

When the snow piles up, it’s tempting to believe that everything is hibernating – or at least waiting for a warmer day. That may be the case for deer and other large animals that have a harder time finding food in deep snow – but not for meadow voles and shrews and other small creatures that live close to the ground. For them, deep snow is an advantage.

That’s because a thick blanket of snow serves a … blanket. Or at least a quilt. All that snow insulates the tunneling-near-the-ground critters from icy winds and freezing temperatures. A layer of snow 6 – 10 inches deep traps heat rising from the ground. That heat melts the snow at the surface. Snowflakes change shape and size, becoming grainy like sugar. They also become less sticky, so small animals can move through that sugar-snow layer.

Scientists have a name for the layer beneath the snow: subnivean (sub= below; nivean refers to snow). They call the grainy crystals “depth hoar”. The Inuit also have a name for that layer of snow, too; they call it “pukak”. 

The blanket of snow blocks the wind, so temperatures in the pukak remain pretty close to freezing all winter long. That may sound cold, but it’s a lot warmer than the air temperature on the surface. Some plants, protected by the thick snow layer, remain green and actively growing – even though they’re getting much less light. Those plants and their roots provide food for the insects and animals that remain active under the snow.

Snow Study

Find a deep, undisturbed snow drift. Using a ruler or a long stick, slice into the drift to expose a cross-section. Examine the different layers you see: thick layer, thin layer, icy, crusty, powdery, dirty. Make a sketch and label the layers. Can you reconstruct the history of snowfalls using your drift-drawing?

Now dig down until you reach the soil layer at the base of your drift. What do you see? Are there any plants? If so, what color are they? Draw or write about signs of animal life – do you see any evidence of tunnels or nests?  Check the soil – is it soft or frozen?

Stick a thermometer horizontally into the snowdrift at different layers. Where is it warmest? Coldest? For more snow study ideas, check out Sandra Markle's blog. And then head over to STEM Friday and see what resources other bloggers are sharing.

Friday, January 24, 2014

A Boy who Loved Math!

The Boy Who Loved Math
by Debora Heiligman; illustrated by LeUyen Pham
44 pages; ages 5 & up
Roaring Brook Press, 2013

Paul Erdos loved numbers and grew up to be one of the greatest mathematicians in the world. And it all started with a big problem …his nanny. Nanny loved rules. Paul didn’t. So he counted the days until his mama returned. And he kept on counting. He added numbers, subtracted numbers, and discovered that you could go the other way beyond zero. Negative numbers – what a cool concept for a young child!

This book describes the life of a very eccentric mathematician who couldn’t tie his shoes but could find patterns for prime numbers. If you’re not too sure about prime numbers, don’t worry -  there’s a great explanation in the story. There are wonderful illustrations of Paul and his college classmates “doing math” around Budapest; they see math in rooftops and steeples.

At the age of 20, Paul was traveling about, giving lectures on math. He couldn’t do his laundry or cook food for himself. Or drive a car or open a carton of orange juice. But boy, could he do math! And people invited him to stay in their homes while he taught classes around the world. Some folks even buttered his toast.

Thankfully (for us mathematically-challenged) both the author and illustrator include great notes for kids (and parents) who want to learn more about Paul. They also include explanations about where the puzzles and graphs come from. This is one picture book that will interest older readers! 

Today's review is part of STEM Friday, where the "M" stands for Math. Find out what other people are reading and doing this week by checking out the STEM Friday Blog. Then on Monday head over to the Nonfiction Monday blog to see what books other bloggers are reviewing.

Friday, January 17, 2014

Ice Watching

We get a lot of ice here in upstate New York... different kinds of ice, depending on the season. Early on, when the cold is a novelty, we like to crunch through the thin frozen ice skins covering puddles. Later, we like to look at things caught in the ice; frozen just beneath the surface.

According to Ellen Obed, there are Twelve Kinds of Ice, each with its own season. Why not spend a few days this winter checking out the kinds of ice you have in your backyard? Is it thick or thin? Is it smooth or bumpy? How many kinds of ice do you have over a winter?

Does your ice sing?

Try tapping on ice with your fingers, a stick, or a spoon. What do you hear? Does thick ice sound different than thin ice? How else can you use ice to make music? Check out how these Siberian drummers make music with the ice on Lake Baikal. The lake is thousands of feet deep, but this section - with the musical ice - is rather shallow... about 5 feet deep.

Getting Traction on a Slippery Surface
If you have a battery-powered toy car, try running it across your icy patch. What sorts of things might you use to help its tires get a grip? Instead of tossing salt on the ice, try some natural things to see if they might help. For example: sand, ashes, tree bark mulch, clean kitty litter, grated beets. Check back during the day to see if any of these things help melt the ice.

The power of Freezing
If you've ever left a plastic bucket of water outside during the winter, you already know that the expansion of freezing water can leave a crack down the side of your bucket. That force of freezing water is one thing that helps break rocks apart. I wonder if it might be used to split those huge logs sitting by my woodpile?

Check out other science resources and book reviews at the STEM Friday blog.

Friday, January 10, 2014

Design, Create... Engineer

If the bitter cold has kept you inside and you're looking for something to do, gather up some odds and ends and see what you can design. That "E" in STEM is for "engineering": designing, inventing, creating.

It doesn't take much to create new things - all you need are some scratched CD's, toilet paper tubes, marbles, glue, batteries, mousetraps, maybe a motor and some dominoes. Then devise a solution to a problem.

What sort of problem? Hm-m-m... maybe a way to squeeze all the toothpaste out of the tube, or a "card-holder" so the little one can join in the games. Or maybe a "waker-upper" that will make sure older brother gets up and out of bed in time to get to school. Or race cars to run around the kitchen floor or a way to make them go up the stairs. Or a an elevator to haul your books (and midnight snacks) up to the second floor.

Sometimes good ideas come from the trash bin. That's what happened when 12-year old Max Wallack figured out how to put styrofoam packing noodles and plastic grocery bags to use building a small dome shelter. Or when my kids decided to make kitchen hockey sticks from gift-wrap tubes and plastic bottles. The pucks: a couple plastic lids duct-taped together. Goal: the thin space under the stove, of course. (next invention: something to retrieve puck)

Some inventions are just for fun - like Rube Goldberg machines that turn a page or start a car. But all inventions, whether purposeful or just for fun, start with ideas.

One way to nurture inventors and engineers of the future is to fill their shelves with books, like Rosie Revere, Engineer, or The Kite That Bridged Two Nations. Both feature characters with can-do attitudes.

Then, make sure you keep a junk box or two filled up with stuff - and allow space for all that messy creativity to happen.

And bookmark this site for when your kids ask, "what does an engineer do anyway?"

Remember to head over to STEM Friday and check out what other bloggers are sharing today.

Friday, January 3, 2014

No Icicles? Make your Own

Nothing says "winter" like icicles. Those are the frozen spikes that form when dripping water freezes.

If you don't have icicles (yet), and it's cold outside, you can make your own. All you need are:
some coffee cans (or #10 cans)
hammer and nail
food coloring

First you need to make something that holds water, but leaks: a can. Start by using the nail to punch three holes around the top rim of each can - evenly spaced. Tie a string through each hole and bring the ends together and tie them in a loop. That's so you can hang your icicle-makers from a tree branch away from sidewalks and driveways.

Then, use the thumbtack to make a hole in the bottom of each can. Make one hole as tiny as possible, and the others of various sizes. On a cold night, cold enough to freeze the water, take your cans outside and fill them half full with water. Add food coloring for tinted icicles. Then hang each icicle-making can on a branch and let it go to work.

In the morning, check on your icicles. Did the size of the hole in the bottom of the can make any difference in the size of your icicles? What happens to them during the day?

One thing you might notice about your icicles is that they all have a "carrot" shape. There's a reason for that, say scientists.As water drips onto an icicle and freezes, it releases heat. The warm air rises up the sides of the icicle and acts like a blanket, or insulator. The insulation is very thin at the tip, and thick at the top. So that's why the tip grows thin and rapidly, and the top grows slowly. Find out more about the math behind icicles here.